The invention relates to a process for separating a fluid feed mixture containing hydrocarbon oil and an organic solvent.
It is known to separate various hydrocarbon compounds from feed mixtures containing said compounds and a solvent by contacting the feed mixture at elevated pressure with one (feed) side of a membrane and recovering solvent and optionally one or more hydrocarbon compounds from the other (permeate) side of the membrane.
However, a major disadvantage of said known separation processes is that a sharp separation into a solvent fraction and a single hydrocarbon oil fraction is not attained therewith; hydrocarbons remain present at both sides of the membranes. Moreover, in case a feed mixture with a relatively high solvent:oil ratio has to be separated, it would be necessary to employ relatively large membrane areas to obtain a given quantity of solvent-poor hydrocarbon oil at the feed side of the membrane.
Surprisingly, it has now been found that the afore-mentioned disadvantages can be overcome by contacting said fluid feed mixture with one side of a hydrocarbon oil-selective membrane which is substantially impermeable to the organic solvent(s) present in the feed mixture and recovering hydrocarbon oil permeate from the other side of the membrane.